Flow Characteristics with Variations of Cut-Off Angle of Multi-Blade Fan for Ventilation

摘要

This study investigated on details of flow characteristics of a multi-blade fan for domestic. ventilation. Experiments and analysis were caned out to describe on flow pattern with variations of cut-off angle near the scrollhousing throat, which were performed by PIV measurement for the flow field and by total pressure probes. The stagnation point at cut-off region of the fan moves to the exit of the scroll housing as cut-off angle increases. The movement of stagnation point and the variation of throat area of Me scroll housing influence to the distribution of velocity magnitude at the exit of the fan. Furthermore, a large distortion of the velocity distribution at the scroll exit causes to increase mixing loss along the flow path. The improvement of the fan design on cut-off is expected through understanding the flow pattern.